WHAT HAVE YOU CHANGED YOUR MIND ABOUT? Today's Leading Minds Rethink Everything. Edited by John Brockman. Harper Perennial, $14.95, paper.

...Last year's question, "What have you changed your mind about?," brought a typically brilliant array of brief essays, by turns provocative, playful and profound. Last year's question, "What have you changed your mind about?," brought a typically brilliant array of brief essays, by turns provocative, playful and profound. Brockman has collected them into a volume with the question as its title.

In one of the essays, MIT quantum-mechanical engineer Seth Lloyd describes how his students have given him a new appreciation of technology. In another, mathematicianKeith Devlin explains his growing conviction that human mathematics is peculiar to the human mind. Nature news editor Oliver Morton has abandoned his support for human spaceflight. And journalist Charles Seife, who once assumed that democracy and science shared the same ideals, now believes that the egalitarian and the skeptic are natural opponents.

These contributions are typically only two or three pages long, which makes them compulsively readable. The only disappointment is that there's no discussion among the participants—but that's what the Web site is for.—Greg Ross